The present invention relates to light assemblies, and more particularly, to hydrodynamic light assemblies which are adapted to be mounted on deep submersible vehicles.
Both manned and remotely piloted deep submersible vehicles are typically equipped with external light assemblies for illuminating adjacent regions of the water and/or features otherwise hidden in virtual darkness. Such light assemblies must of course be capable of withstanding extremely high water pressures, e.g. 16,500 PSI hydrostatic pressure. They must also be capable of accommodating high internal lamp temperatures, and low external water temperatures, e.g. slightly below zero degrees C. They must also be capable of providing a high degree of illumination since practically no light from the surface penetrates to depths below several thousands of feet. Furthermore, visibility is frequently impaired by suspended particulate matter and other debris which can only be ameliorated with intense, controlled illumination. Such light assemblies must not have undue power consumption because these vehicles typically operate on battery power. They must have a reasonable degree of shock resistance in case the vehicle should collide with some obstruction during a mission.
One deep submersible light assembly that satisfies the foregoing criteria is disclosed in U.S. Pat. No. 4,683,523 granted July 28, 1987 to Mark G. Olsson et al. In that assembly, a quartz-halogen lamp is mounted to the forward end of a cylindrical metal sleeve screwed over the end of a hollow metal body. The lamp is surrounded by a relatively small protective glass envelope which is held within a cavity in the forward end of the sleeve by a special high pressure radial seal. A removable reflector fits over the forward ends of the sleeve and body, surrounding and enclosing the lamp and its protective envelope. A perforated transparent dome-shaped cover fits over the forward end of the reflector. Water flows into the reflector cavity and directly contacts the protective envelope, otherwise the reflector would collapse from the tremendous water pressures encountered. The reflector is made of an inner body defining a parabolic or other reflecting surface and an outer protective body. These reflector bodies are made of cast polyurethane, DELRIN (Trademark), Aluminum or other suitable material capable of absorbing blows. They can be shaped for different mission requirements, e.g. spot or flood.
While the foregoing patented lamp assembly has been quite successful, it has been found that particles of matter suspended in the water inside the reflector and behind the dome-shaped cover can significantly affect the efficiency of the reflector. If one were to design a deep submersible light assembly in which the water does not enter the reflector, i.e. a "dry" reflector type light assembly, it would require some sort of transparent cover and seal assembly that could withstand tremendous water pressures without rupturing or leaking.